Leopard Frog PFOS & PFHxS Mixture Study

<p>PFAS at aqueous film forming foam (AFFF) impacted sites occur as mixtures, with perfluorooctanesulfonic acid (PFOS) and perfluorohexanesulfonic acid (PFHxS) most commonly co-occurring in the highest concentrations. Although PFOS and PFHxS toxicities have been studied extensively, few studies have tested potential interactions between the two. This study compared toxicities of a 1:1 PFOS:PFHxS mixture to PFOS and PFHxS individually with the prediction that responses would be additive. Leopard frog tadpoles were exposed to either 0.5 ppb or 1 ppb PFOS or PFHxS singly or a mixture of 0.5 ppb PFOS and 0.5 ppb PFHxS throughout metamorphosis (GS 25 through GS 46).  Survival was monitored throughout the study.  Phenotypic responses (mass, SVL, SMI) were measured at day 31, GS 42 (metamorphic climax), and GS 46 (completion of metamorphosis).  PFAS body burdens were measured at day 31 of exposure and at GS 46, BCFs were calculated at GS 46.  </p>